1. The Field of the Invention
This invention relates in general to contaminated soil remediation and in particular to hydrocarbon contaminated soil remediation from underground storage tanks applications.
2. The Description of Related Art
There are approximately 3 million underground storage tanks in the United States, most of which are used to contain petroleum products. Many of these have been or will be leaking, contaminating the soil and leaching into the groundwater. In order to comply with USEPA act 40 CFR-280 these tanks must be removed and all contaminated soil treated.
Traditional methods of treatment include incineration, landfilling, or biological remediation. Incineration consists of using heat to burn off the hydrocarbons and either replacing the soil in the excavation, landfilling it, or using it under road surfaces or in asphalt. This method sterilizes the soil destroying all beneficial microbes and also leaves behind an ash residue and heavy metals which must be landfilled. Due to the decreasing availabilities of landfill space and the need to reserve space for materials which cannot as yet be recycled, the landfill option of disposal is becoming increasingly unpopular and costly for items such as petroleum contaminated soil. Bioremediation of hydrocarbon contaminated soils takes a long time to accomplish, takes up much space and still doesn't address the problem of heavy metal contamination such as lead from leaded gasolines.
Other methods of treating petroleum contaminated soil have been along the lines of mixing into hot mix asphalt or as an aggregate in a high strength concrete. Either method prohibits leaching of contaminates into the groundwater, but neither involves on site remediation which is a safer and preferred method of treatment.